An adjustable blade root spring device for turbine blade fixation in turbomachinery. The device is designed to be placed in a space in a rotor disk cavity adjacent to a tip of a blade root, where the device applies a radial outward force on the turbine blade to fix the blade position in the rotor disk. The device includes a wave spring with integral end blocks which is compressed by a bolt and a coil spring. When the wave spring is compressed in length, it increases in height and makes contact with the rotor disk and the turbine blade. The force of the wave spring on the turbine blade can be adjusted via the bolt, and the coil spring provides an increased compliance range. The body of the device has an oblong cross-sectional shape, thereby preventing rotation of the device in the space between the blade and the disk.